Reprinted with permission from The Washington Monthly.

Talk of the 2020 election has focused primarily on polling, whether it involves the Democratic primary or potential face-to-face match-ups with Trump. But in The Atlantic, Ron Brownstein took a look at something equally important: voter turnout. Political scientists are forecasting a veritable tsunami.

Signs are growing that voter turnout in 2020 could reach the highest levels in decades—if not the highest in the past century—with a surge of new voters potentially producing the most diverse electorate in American history…

With Donald Trump’s tumultuous presidency stirring such strong emotions among both supporters and opponents, strategists in both parties and academic experts are now bracing for what Michael McDonald, a University of Florida political scientist who specializes in voting behavior, recently called “a voter turnout storm of a century in 2020.”

In a recent paper, the Democratic voter-targeting firm Catalist projected that about 156 million people could vote in 2020, an enormous increase from the 139 million who cast ballots in 2016. Likewise, Public Opinion Strategies, a leading Republican polling firm, recently forecast that the 2020 contest could produce a massive turnout that is also unprecedentedly diverse.

McDonald is forecasting that two-thirds (67 percent) of eligible voters will cast a ballot in 2020. Here is how that compares with recent history.

Since 18-year-olds were granted the vote [in 1972], the highest showing was the 61.6 percent of eligible voters who showed up in 2008, leading to Barack Obama’s victory. And since World War II, the highest turnout level came in 1960, with John F. Kennedy’s win, when 63.8 percent of voters participated.

It is worth noting that in both of those cases a young, dynamic Democrat was running against an older establishment Republican. In one instance, the Democrat went on to become the first Catholic president in the country’s history, while the other became the first African-American president.

Recent predictions are based on data points like the number of small contributions to presidential campaigns, cable news viewership, and polls indicating a high degree of interest in the election. But it also reflects what happened in the 2018 midterms, in which 35 million more people participated than in 2014. Here is the good news for Democrats.

McDonald estimates that the number of eligible voters increases by about 5 million each year, or about 20 million from one presidential election to the next. That increase predominantly flows from two sources: young people who turn 18 and immigrants who become citizens. Since people of color are now approaching a majority of the under-18 population—and also constitute most immigrants—McDonald and other experts believe it’s likely that minorities represent a majority of the people who have become eligible to vote since 2016.

However, that only matters if the newly eligible voters actually turn out on Election Day—which is exactly what happened in 2018.

Turnout typically falls for all voter groups in midterm elections compared with the previous presidential race, but that falloff was much smaller than usual last year. Moreover, while turnout surged across virtually all groups, it increased most sharply among the voters who historically have participated at the lowest levels.

In addition to voter suppression, here is what Republicans are counting on.

The electorate is not diversifying nearly as fast in the three Rust Belt states that Trump dislodged from the Blue Wall—Michigan, Pennsylvania, and Wisconsin. Those states, for years to come, will remain older and whiter than the nation overall, meaning that to win them, Democrats have to run better with older, whiter voters than they do in most places.

But Trump faces an uphill battle in those Rust Belt states right now, where his approval rating stands at -7 in Pennsylvania, -12 in Michigan, and -13 in Wisconsin. He’s going to need to energize a lot of angry white non-college-educated males in those states to turn that around.